Object detection apparatus, and storage medium

ABSTRACT

An object detection apparatus includes an input port that receives information on a plurality of objects in surroundings of a vehicle and information on a traffic environment of the vehicle, the plurality of objects being detected by a sensor installed on the vehicle, a controller that determines, based on the information on the plurality of objects and the information on the traffic environment, priority for each of the plurality of objects and determines first information based on the priority in a case where the total amount of information on the plurality of objects is greater than a determined value, the first information being information on part of the plurality of objects, and an output port that outputs the first information to an in-vehicle apparatus that controls the vehicle.

BACKGROUND 1. Technical Field

The present disclosure relates to an object detection apparatus thatoutputs, to an in-vehicle apparatus, information on an object detectedby a sensor installed on a vehicle, and a storage medium.

2. Description of the Related Art

A type of an object detection apparatus is disclosed, for example, inJapanese Unexamined Patent Application Publication 2007-232412. Thisobject detection apparatus includes a detection unit that detects anobject using a radar and a selection unit. The detection unit detects ahigh-threshold object with a reflection intensity higher than a firstthreshold value and a low-threshold object with a reflection intensitylower than the first threshold value and higher than a second thresholdvalue. The selection unit performs selection such that in a case wherethe sum of the number of candidates for the high-threshold objectsdetected by the detection unit and the number of candidates for thelow-threshold objects is greater than a preset maximum allowable numberof objects capable of being output as a detection result, the selectionunit selects, as the detection result, high-threshold objects andlow-threshold objects such that a higher priority is given to thecandidates for high-threshold objects.

SUMMARY

In the known object detection apparatus, the priority of objects to bedetected is determined based on the reflection intensity. However,objects to be detected for a vehicle may be different depending on atraffic environment.

One non-limiting and exemplary embodiment facilitates providing anobject detection apparatus, and a storage medium capable of outputtinginformation on an object depending on a traffic environment.

In one general aspect, the techniques disclosed here feature an objectdetection apparatus including an input port that receives information ona plurality of objects in surroundings of a vehicle and information on atraffic environment of the vehicle, the plurality of objects beingdetected by a sensor installed on the vehicle, a controller thatdetermines, based on the information on the plurality of objects and theinformation on the traffic environment, priority for each of theplurality of objects and determines first information based on thepriority in a case where the total amount of information on theplurality of objects is greater than a determined value, the firstinformation being information on part of the plurality of objects, andan output port that outputs the first information to an in-vehicleapparatus that controls the vehicle.

According to the present disclosure, it is possible to facilitateproviding an object detection apparatus and a storage medium, capable ofoutputting information on an object depending on a traffic environment.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a hardware configuration of an object detectionapparatus according to the disclosure and a configuration of aperipheral configuration;

FIG. 2 illustrates functional blocks of an object detection apparatusaccording to a first embodiment;

FIG. 3 illustrates a flow of a process performed by the object detectionapparatus shown in FIG. 2;

FIG. 4 illustrates functional blocks of an object detection apparatusaccording to a first modification;

FIG. 5 illustrates a flow of a process performed by the object detectionapparatus shown in FIG. 4;

FIG. 6 illustrates functional blocks of an object detection apparatusaccording to a second modification; and

FIG. 7 illustrates a flow of a process performed by the object detectionapparatus shown in FIG. 6.

DETAILED DESCRIPTION

Referring to drawings, the present disclosure is described in furtherdetail below with reference to embodiments of object detectionapparatuses 1, 1A, and 1B, programs 137, 137A, and 137B, and a storagemedium storing the program 137, 137A, or 137B.

1. Embodiments

First, an object detection apparatus 1 according to an embodiment of thepresent disclosure is described.

1-1. Configuration of Object Detection Apparatus 1 and PeripheralConfiguration

In FIG. 1, a vehicle V includes, as apparatuses installed therein, inaddition to the object detection apparatus 1 described above, a sensor3, a traffic environment transmission apparatus 5, and an in-vehicleapparatus 7. In the present disclosure, it is possible to perform datatransmission via a data transmission line 9, using a particular datatransmission method, between the object detection apparatus 1 and eachof other apparatuses including the sensor 3, the traffic environmenttransmission apparatus 5, and the in-vehicle apparatus 7. Examples ofthe data transmission method include Controller Area Network (CAN),Ethernet (registered trademark), etc.

First, the sensor 3 and the traffic environment transmission apparatus 5are described. The sensor 3 is, for example, a millimeter wave radar,and is installed, for example, near the front end of the vehicle V. Forexample, the sensor 3 periodically transmits a radar signal (forexample, a radio wave in a millimeter wave band) within a measurablerange (in other words, in a visible range). When the sensor 3 receives,via its receiving antenna, a return signal which is a radar signaloutput and reflected back from an object (target object), the sensor 3executes a known target recognition algorithm. As a result, a direction,a distance, a relative speed, a return signal strength, and/or the likeof an object (typically a moving object) existing in surroundings of thevehicle V are detected time-sequentially. The sensor 3 time sequentiallytransmits target information T associated with each object existing inthe surroundings of the vehicle V to the object detection apparatus 1via the data transmission line 9. In the present disclosure, the targetinformation T includes items such as the direction, the distance, therelative speed, and/or the like of the object with reference to thevehicle V (or the sensor 3).

The traffic environment transmission apparatus 5 is, for example, anavigation apparatus. For example, the traffic environment transmissionapparatus 5 is capable of identifying a current location of the vehicleV (more specifically, the current position of the sensor 3) and capableof acquiring network data representing a road distribution expressedtypically using links and nodes from a local storage device (notillustrated) or a remote server. Each node represents a feature point(an intersection or a bending point) on a road. Each link represents aroad between each of nodes. Each link is assigned various kinds ofinformation on a road, such as a road type or the like. Examples of roadtypes include an expressway, a general road, a road close to anintersection, and the like.

The traffic environment transmission apparatus 5 identifies, in responseto a request from the object detection apparatus 1, a road on which thevehicle V is currently running, and acquires traffic environmentinformation E including a type of the identified road from network data.The traffic environment transmission apparatus 5 transmits the acquiredtraffic environment information E to the object detection apparatus 1via the data transmission line 9.

The object detection apparatus 1 is disposed, for example, in anElectronic Control Unit (ECU), and includes an input port 11, acontroller 13, and an output port 15.

The input port 11 is an input interface according to the datatransmission method described above. The input port 11 receives targetinformation T from the sensor 3 and traffic environment information Efrom the traffic environment transmission apparatus 5. Furthermore,under the control of the controller 13, the input port 11 transfers thereceived target information T and the traffic environment information Eto a main memory 133 of the controller 13.

The controller 13 includes, for example, a program memory 131, the mainmemory 133, and a microcomputer 135.

The program memory 131 is, for example, a non-transitory memory such asEEPROM. In the program memory 131, a program 137 describing a processingprocedure (described later with reference to FIG. 3) is stored inadvance.

The main memory 133 is, for example, a semiconductor memory such asSRAM.

The microcomputer 135 executes the program 137 using the main memory 133or the like as a work area. Basically, the microcomputer 135 transmitsall received target information T to the in-vehicle apparatus 7 via thedata transmission line 9. However, in a case where it is impossible totransmit all received target information T, the microcomputer 135selects target information with high priority from the received targetinformation T, and transmits the selected target information with highpriority to the in-vehicle apparatus 7 via the data transmission line 9.

The output port 15 is an output interface according to the datatransmission method, and transmits target information T to thein-vehicle apparatus 7 via the data transmission line 9 each time thetarget information T to be transmitted is determined by themicrocomputer 135.

The in-vehicle apparatus 7 is an apparatus such as a display apparatus,an automatic braking apparatus, or the like installed in the vehicle V,and performs a particular process based on a detection result R receivedfrom the output port 15.

1-2. Process Performed by Controller 13

In the controller 13, as described above, the microcomputer 135 executesthe program 137 thereby functioning as a target acquirer 171, adeterminer 173, a priority assigner 175, a traffic environment acquirer177 and a target outputter 179, as illustrated in FIG. 2. Next,referring to FIG. 1 to FIG. 3, an operation by the object detectionapparatus 1 (for example, a processing procedure of the microcomputer135 defined in the program 137) is described below.

The target information T transmitted time-sequentially from the sensor 3is received by the input port 11. First, the microcomputer 135 functionsas the target acquirer 171 and transfers the received target informationT to the main memory 133. As a result, the controller 13 acquires thetarget information T (step S001 in FIG. 3).

After step S001, the microcomputer 135 functions as the determiner 173,and determines whether it is possible to transmit all target informationT acquired in step S001 to the in-vehicle apparatus 7 (step S003). Morespecifically, the transmission bandwidth usable in the data transmissionfrom the object detection apparatus 1 to the in-vehicle apparatus 7 islimited to a predetermined fixed value. Furthermore, the transmissionfrom the target information T to the in-vehicle apparatus 7 generallyneeds to be performed in real time. Thus, in step S003, it is determinedwhether it is possible to transmit all target information T received bythe object detection apparatus 1 to the in-vehicle apparatus 7 using ausable transmission bandwidth within a predetermined period of time. Inother words, it is determined whether the data output rate (transmissionbandwidth) [bits/sec] at the output port 15×output time (predeterminetime period) [sec] is larger than the total amount of data [bits] of theacquired target information T.

In a case where it is determined in step S003 (by the determiner 173)that it is possible to transmit all target information T (Yes in stepS003), then the microcomputer 135 functions as the target outputter 179and transmits all target information T acquired in step S001 to thein-vehicle apparatus 7 (step S027). After step S027, the microcomputer135 returns the process to step S001, in which the microcomputer 135performs a process shown in FIG. 3 on the target information T that theinput port 11 newly receives from the sensor 3 via the data transmissionline 9.

On the other hand, in a case where it is determined in step S003 (by thedeterminer 173) that it is impossible to transmit all target informationT (No in step S003), the microcomputer 135 functions as the priorityassigner 175 and determines an initial priority for each piece ofinformation included in the whole target information T acquired in stepS001 and sorts the pieces of information in the target information T inorder of priority from high to low (step S005). In this step S005, forexample, the closer the distance between the vehicle V (or the sensor 3)and the object described in a piece of information in the targetinformation T, the higher the priority assigned to the piece in thetarget information T.

Next, the microcomputer 135 functions as the traffic environmentacquirer 177 and acquires traffic environment information E from thetraffic environment transmission apparatus 5. In the present disclosure,the traffic environment information E represents a traffic environmentin the surroundings of the vehicle V, and more specifically the trafficenvironment information E includes information indicating a type of aroad on which the vehicle V is currently running (hereinafter referredto as a road type). Examples of road types include an expressway, ageneral road, a road close to intersection, and the like. The trafficenvironment information E is received by the input port 11. Themicrocomputer 135 transfers the received traffic environment informationE to the main memory 133. As a result, the controller 13 acquires thetraffic environment information E (step S007).

Next, the microcomputer 135 functions as the priority assigner 175 anddetermines whether the road type described in the traffic environmentinformation E is the expressway, the road close to intersection, or thegeneral road (steps S009, S011, and S013).

In a case where the road type is the expressway, the microcomputer 135advances the processing flow from step S009 to step S015, in which themicrocomputer 135 changes the priority of pieces of information includedin the target information T currently stored in the main memory 133 suchthat the priority of a piece of information associated with an oncomingvehicle is reduced by a first predetermined value (step S015). Thisprocess is performed because expressways each have a center divider andthus oncoming vehicles do not have significant influences on running ordriving of the vehicle V. The determination as to whether the targetinformation T indicates an oncoming vehicle or not may be performedbased a relative speed and a direction described in the targetinformation T. The first predetermined value may be properly determinedwhen the object detection apparatus 1 is designed or developed. In acase where the road type is not the expressway, the microcomputer 135advances the processing flow from step S009 to step S011.

In a case where the road type is the road close to intersection, themicrocomputer 135 advances the processing flow from step S011 to stepS017, in which the microcomputer 135 changes the priority of pieces ofinformation included in the target information T currently stored in themain memory 133 such that the priority of a piece of informationassociated with an oncoming vehicle is increased by a secondpredetermined value (step S017). This process is performed because, onthe road close to intersection, oncoming vehicles have significantinfluences on running or driving of the vehicle V. More specifically,when the vehicle V runs straight or makes a right turn at anintersection, the running or driving of the vehicle V may be influencedby an oncoming vehicle running straight or making a right turn. Thedetermination as to whether a piece of information in the targetinformation T indicates an oncoming vehicle or not may be performedbased a relative speed and a direction described in the targetinformation T. The second predetermined value may be properly determinedwhen the object detection apparatus 1 is designed or developed. In acase where the road type is not the road close to intersection, themicrocomputer 135 advances the processing flow from step S011 to stepS013.

In a case where the road type is a general road, the microcomputer 135advances the processing flow from step S013 to step S019, in which themicrocomputer 135 changes the priority of pieces of information includedin the target information T currently stored in the main memory 133 suchthat the priority of a piece of information associated with a vehicleapproaching the vehicle V at a high speed is increased by a thirdpredetermined value (step S019). This process is performed because therunning and the driving of the vehicle V are influenced by movingobjects (mainly vehicles) located near the vehicle V and approaching thevehicle V at a high speed. In the present disclosure, the initialpriority for each piece of information in the target information T isdetermined, in step S005, depending on the distance between the vehicleV and the object, and thus, in step S019, the priority is increased fora vehicle approaching the vehicle V at a high speed. The determinationas to whether a piece of information in the target information Tindicates a vehicle approaching the vehicle V at a high speed may beperformed based a relative speed and a direction described in the targetinformation T. The third predetermined value may be properly determinedwhen the object detection apparatus 1 is designed or developed.

After steps S015, S017, and S019 described above, the microcomputer 135functions as the target outputter 179 and sorts the pieces ofinformation in the target information T currently stored in the mainmemory 133 in order of priority from high to low (step S021).

After step S021 or in a case where the answer to step S013 is No, themicrocomputer 135 functions as the target outputter 179 and selects,from the target information T currently stored in the main memory 133,pieces of information that the object detection apparatus 1 can outputto the in-vehicle apparatus 7 within the predetermined time perioddescribed above based on the priority assigned to the pieces ofinformation (step S023).

The microcomputer 135 further functions as the target outputter 179 andsequentially transmits the pieces of information selected in step S023in the target information T, for example, in order of priority from highto low, to the data transmission line 9 via the output port 15 (stepS025). The transmitted pieces of information of the target information Tare received by the in-vehicle apparatus 7 via the data transmissionline 9. In a case where the in-vehicle apparatus 7 is a displayapparatus, an object existing in the surroundings of the vehicle V isdisplayed based on the received target information T to call attentionof a driver of the vehicle V. If the in-vehicle apparatus 7 is anautomatic braking apparatus, braking of the vehicle V is controlled, asrequired, to reduce the speed of the vehicle V or stop the vehicle Vbased on the received target information T.

After step S025, the microcomputer 135 returns the processing flow tostep S001, in which the microcomputer 135 performs a process shown inFIG. 3 on the target information T that the input port 11 newly receivesfrom the sensor 3 via the data transmission line 9.

1-3. Operations and Effects of Object Detection Apparatus 1

In the object detection apparatus 1, as described above, the input port11 receives, from the sensor 3, the target information T includingpieces of information associated with respective objects existing in thesurroundings of the vehicle V, and also receives traffic environmentinformation E representing the traffic environment in the surroundingsof the vehicle V from the traffic environment transmission apparatus 5.In the controller 13, the target acquirer 171 stores the targetinformation T received via the input port 11 in the main memory 133. Thetraffic environment acquirer 177 stores the traffic environmentinformation E received via the input port 11 in the main memory 133.

The priority assigner 175 determines the priority for each of aplurality of objects (described in the target information T) based onthe target information T and the traffic environment information Etaking into account the influence of the current traffic environment onthe running of the vehicle V. In a case where the total amount of dataof the target information T in the main memory 133 is larger than thepredetermined value, the target outputter 179 selects pieces ofinformation from the target information T stored in the main memory 133according to the priority determined by the priority assigner 175 andtransmits the selected pieces of information to the data transmissionline 9 toward the in-vehicle apparatus 7. Note that the priorityassigner 175 retains the remaining part of the target information T ofobjects in the main memory 133.

Thus, it is possible to provide the object detection apparatus 1 and theprogram 137 capable of limiting the target information T on objects tobe output depending on the traffic environment. In particular, theobject detection apparatus 1 according to the present disclosure limitsthe target information T output to the data transmission line 9 topieces of information associated with objects being highly likely tohave an influence on the running of the vehicle V in the current trafficenvironment. This makes it possible to transmit the target information Tto the in-vehicle apparatus 7 without missing part of the targetinformation T used in safely driving the vehicle V in the currenttraffic environment.

Furthermore, in the present object detection apparatus 1, in step S025,pieces of information included in the target information T aretransmitted sequentially in order of priority from high to low to thedata transmission line 9, and thus it is possible for the in-vehicleapparatus 7 to quickly receive part of the target information T onobjects having a possibility of exerting a significant influence ondriving the vehicle V. Therefore, the object detection apparatus 1 iscapable of having a large contribution to safe driving of the vehicle V.

1-4. Supplement

In the embodiment described above, it is assumed by way of example, forconvenience of explanation, that the traffic environment information Eincludes information on a road type. However, the traffic environmentinformation E is not limited to the information on the road type, butthe traffic environment information E may be any information as long asthe information has an influence on the running of the vehicle V or thepriority of objects. For example, the traffic environment information Emay be information representing a road width, a line shape, a slope, acrossing cant, paving of road, a pedestrian-vehicle separation, or acenter division, or a combination of two or more of these items. Therunning of the vehicle V and/or the priority of objects are basicallydependent on the road characteristics such as those described above, butare also influenced by presence/absence of buildings in thesurroundings, weather conditions, or the like. In view of this fact, thetraffic environment information E may include information aboutbuildings close to a road on which the vehicle V is currently running,and/or information about a current weather condition.

FIG. 3 also illustrates a processing procedure performed in a case wherethe traffic environment information E includes information indicating aroad type such as an expressway, a road close to intersection, or ageneral road. Note that the processing procedure in FIG. 3 may beproperly defined depending on what kind of information is included inthe traffic environment information E.

In the embodiment described above, in step S005, the smaller thedistance between the vehicle V and an object, the higher the priorityassigned to the object. However, the initial priority may be assignedbased on another criterion. For example, the higher the running speed ofthe vehicle V and an object, the higher the priority assigned to theobject.

In the embodiment described above, it is assumed by way of example thatthe traffic environment transmission apparatus 5 is a navigationapparatus. However, the traffic environment transmission apparatus 5 isnot limited to the navigation apparatus, but the traffic environmenttransmission apparatus 5 may be an in-vehicle apparatus capable ofperforming a road-to-vehicle communication with an apparatus installedon a side of a road on which the vehicle V is running and acquiringtraffic environment information E such as that described above. Thesensor 3 may also be capable of acquiring part of the trafficenvironment information E, and thus the traffic environment transmissionapparatus 5 may be the sensor 3.

In the embodiment described above, it is assumed by way of example thatthe sensor 3 is a millimeter wave radar. However, the sensor 3 is notlimited to the millimeter wave radar but the sensor 3 may be, forexample, a laser radar, a camera, or the like. The sensor 3 may be acombination of two or more of the millimeter wave radar, the laserradar, and the camera.

In the embodiment described above, in view of the transmission bandwidthof the data transmission line 9, the determination in step S003 as towhether the target information T can be transmitted or not is performedby determining whether the data output rate×the output time is largerthan the total amount of data of the target information T. However, themethod of determining whether all target information T can betransmitted is not limited to the example described above. For example,the determination may be performed based on the viewability of thedisplay apparatus employed as the in-vehicle apparatus 7. In this case,when it is determined in step S003 that the total number of objectsdescribed in the target information T is larger than a predeterminedvalue, steps S005 to S025 may be performed. By performing the process inthis manner, it becomes possible to limit the number of objectsdisplayed at the same time on the display apparatus, which makes itpossible for a driver to easily recognize a plurality of objectsexisting in the surroundings of the vehicle V.

In the embodiment described above, it is assumed by way of example thatthe program 137 is stored in the program memory 131. However, thestorage in which the program 137 is stored is not limited to the programmemory 131. For example, the program 137 may be stored in acomputer-readable storage medium (for example, a DVD or the like).Alternatively, the program 137 may be stored in a server apparatus, andthe program 137 may be downloaded to various terminal apparatuses (forexample, a desktop personal computer, a smartphone, a tablet terminal,or the like). This also holds for programs 137A and 1376 describedlater.

2. First Modification

Next, a first modification of the object detection apparatus 1 isdescribed below.

2-1. Configuration and Process According to First Modification (ObjectDetection Apparatus 1A)

First, an object detection apparatus 1A according to the firstmodification of the embodiment is described. In FIG. 1, the objectdetection apparatus 1A is different from the object detection apparatus1 in that not the program 137 but a program 137A is stored in theprogram memory 131. In the object detection apparatus 1A, similarelements to those in the object detection apparatus 1 are denoted bysimilar reference symbols, and a further description thereof is omitted.

In the control unit 13, the microcomputer 135 executes the program 137Athereby functioning as a target tracker 191 in addition to thefunctional blocks 171 to 179 described above, as shown in FIG. 4. Next,referring to FIG. 5, a processing procedure defined in the program 137Aand performed by the microcomputer 135 is described in detail below. Theprocessing flow shown in FIG. 5 is different from that shown in FIG. 3in that the processing flow additionally includes steps S101 and S102.In FIG. 5, similar steps to those in FIG. 3 are denoted by similar stepnumbers, and a further description thereof is omitted or given in asimplified manner.

After step S001, the microcomputer 135 performs S003. In a case where itis determined in S003 that it is difficult to transmit all targetinformation T (No in S003), the microcomputer 135 functions as thetarget tracker 191 and performs a target tracking process in step S101.In the target tracking process, the target tracker 191 tracks, on a timeaxis, the same object described in time-sequential target information Tusing current and past (for example, previous) target information T. Bytracking the same object in the time-sequential target information T, itbecomes possible to enhance the reliability of the target information Tregarding the object. In other words, it is possible to achieve a higherpossibility that the object of interest actually exists in thesurroundings of the vehicle V. Furthermore, the target tracker 191transfers the information representing the existence probability, thenumber of times the tracking was successful, and the informationindicating the level of confidence of the target information T(hereinafter referred to simply as confidence level) based on the resultof the tracking process to the priority assigner 175. Thus the processin step S101 is completed.

In the first modification, after step S101 is completed, themicrocomputer 135 performs steps S005 to S019 described above.Thereafter, the microcomputer 135 functions as the priority assigner 175and changes the priority for the corresponding target information Tbased on the confidence level of each object received in the step S101(step S102). In step S102, for example, the priority for the targetinformation T with a confidence level higher than a reference value isincreased by a fourth predetermined value, and the priority for thetarget information T with a confidence level equal to or lower than areference value is reduced by a fifth predetermined value. The fourthpredetermined value and the fifth predetermined value may be set in asimilar manner for the predetermined values described above. Thereafter,the microcomputer 135 performs steps S021 to S027 described above.

2-2. Operations and Effects of Object Detection Apparatus 1A

According to the first modification, it is possible to transmit targetinformation T, which is necessary in safely driving in the currenttraffic environment, to the in-vehicle apparatus 7 without missingtarget information T associated with an object highly likely to actuallyexist.

2-3. Supplement on First Modification

In the first modification, step S101 is performed immediately after stepS003. However, there is no restriction on the timing of performing stepS101 as long as step S101 is performed after step S001 and before stepS102.

3. Second Modification

Next, a second modification of the object detection apparatus 1 isdescribed below.

3-1. Configuration and Process According to Second Modification (ObjectDetection Apparatus 1B)

Next, an object detection apparatus 1B according to the secondmodification of the embodiment is described. In FIG. 1, the objectdetection apparatus 1B is different from the object detection apparatus1 in that not the program 137 but a program 137B is stored in theprogram memory 131. In the object detection apparatus 1B, similarelements to those in the object detection apparatus 1 are denoted bysimilar reference symbols, and a further description thereof is omitted.

In the control unit 13, the microcomputer 135 executes the program 137Bthereby functioning as an information remover 193 in addition to thefunctional blocks 171 to 179 described above, as shown in FIG. 6. Next,referring to FIG. 7, a processing procedure defined in the program 137Band performed by the microcomputer 135 is described in detail below. Theprocessing flow shown in FIG. 7 is different from that shown in FIG. 3in that the processing flow additionally includes steps S201. In FIG. 7,similar steps to those in FIG. 3 are denoted by similar step numbers,and a further description thereof is omitted or given in a simplifiedmanner.

After steps S001 to S023, the microcomputer 135 functions as theinformation remover 193 (step S201). In the second modification, first,the information remover 193 classifies the pieces of informationselected in step S023 from the target information T such that pieces ofinformation being high in priority are classified in a first group. Thenumber of pieces of information in the target information T classifiedin the first group may be properly determined when the object detectionapparatus 1B is designed or developed. The information remover 193further classifies pieces of information in the target information Tsuch that pieces of information that are selected in step S023 but thatare not classified in the first group and pieces of informationremaining in the target information T without being selected in stepS023 are classified in a second group.

The microcomputer 135 further functions as the information remover 193and removes predetermined items from the pieces of information in thetarget information T classified in the second group. For example, toidentify the location of an object, a distance and a direction describedin target information T have a high relativity, but a relative speed anda signal strength do not have a high relativity. Therefore, themicrocomputer 135 removes the relative speed and the signal strengthfrom each piece of information in the target information T classified inthe second group. As a result, the number of items included in thepieces of information in the target information T classified in thefirst group becomes larger than the number of items included in thepieces of information in the target information T belonging to thesecond group.

Next, the microcomputer 135 functions as the target outputter 179 andtransmits the pieces of information in the target information T selectedin step S023 sequentially, for example, in order of priority from highto low, to the data transmission line 9 via the output port 15 (stepS025). In this process, as for the pieces of information in the targetinformation T classified in the first group, all items thereof aretransmitted. On the other hand, as for the pieces of information in thetarget information T in the second group (that is, information in termsof the distance and the direction), the microcomputer 135 transmits asmany pieces as allowed by the data output rate and the output time.

3-2. Operations and Effects of Object Detection Apparatus 1B

According to the second modification, the predetermined items areremoved from the pieces of information in the target information T inthe second group, and thus the object detection apparatus 1B is capableof transmitting a larger number of pieces of information in the targetinformation T to the in-vehicle apparatus 7 although the number of itemsis reduced. Thus, it is possible to reduce the number of objects thatare not transmitted although they are detected by the sensor 3.

3-3. Other Methods of Classifying Information

In the example described above, the object detection apparatus 1Bremoves information on the relative speed and the signal strength fromthe pieces of information in the target information T classified in thesecond group. However, the items removed by the information remover 193are not limited to these. For example, the information remover 193 maychange one or more items removed from the pieces of information in thetarget information T classified in the second group depending on thetraffic environment information E acquired in step S007. Morespecifically, on expressways, objects located in the surroundings of thevehicle V can be supposed to be vehicles. Therefore, in a case where theanswer to step S009 is Yes, then in step S201, information on the signalstrength is removed from the pieces of information in the targetinformation T belong to the second group. After step S011 or in a casewhere the answer to step S013 is Yes, information on the signal strengthand the relative speed is removed from the pieces of information in thetarget information T classified in the second group.

In a still alternative example, the information remover 193 may dividethe pieces of information in the target information T belonging to thesecond group into n subgroups (1st to nth subgroups), and may outputinformation in the target information T belong to each subgroup to thein-vehicle apparatus 7 at a low rate. More specifically, in step S025 in1st to nth iterations, pieces of information in the target information Trespectively belonging to the 1st to nth subgroups are sequentiallyoutput on a subgroup-by-subgroup basis. By performing the process in theabove-described manner, it is also possible to prevent the targetinformation T detected by the sensor 3 from being missed.

In a still alternative example, in a case where the object detectionapparatus 1B includes the target tracker 191 shown in FIG. 4, if thetarget tracker 191 is capable of successfully tracking the same objectin a time series of target information T, the information remover 193may transmit information such that, of the pieces of information in thecurrent target information T associated with the objects beingsuccessfully tracked, items whose values have changed from past valuesare transmitted regardless of whether the information is in the firstgroup or the second group, and the information remover 193 may removeitems whose values have not changed. In a still alternative example, asfor the second group, items in the current target information Tassociated with objects being successfully tracked may be removed if nochange from the values described in the past target information T isobserved.

3-4. Supplement on Second Modification

In the second modification described above, from the point of view ofreducing the number of objects that are not transmitted although theyare detected by the sensor 3, the information remover 193 classifies thepieces of information selected in step S023 from the target informationT such that pieces of information being high in priority are classifiedin a first group, and the information remover 193 further classifiespieces of information in the target information T such that pieces ofinformation that are selected in step S023 but that are not classifiedin the first group and pieces of information remaining in the targetinformation T without being selected in step S023 are classified in asecond group. However, alternatively, the information remover 193 mayclassify the pieces of information selected in step S023 from the targetinformation T such that pieces of information being high in priority areclassified in a first group, and pieces of information that are selectedin step S023 from the target information T but that are not classifiedin the first group are classified in the second group. The makes itpossible to reduce the transmission bandwidth of the data transmissionline 9 used by the object detection apparatus 1B.

4. Notes

The embodiments and modifications described above are merely examples ofimplementations of the present disclosure, and it is to be understoodthat these examples do not limit the technical scope of the presentdisclosure. That is, it is possible to realize the present disclosure invarious forms without departing from the scope or the main features ofthe present disclosure.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware.

Each functional block used in the description of each embodimentdescribed above can be partly or entirely realized by an LSI such as anintegrated circuit, and each process described in each embodiment may becontrolled partly or entirely by the same LSI or a combination of LSIs.The LSI may be individually formed as chips, or one chip may be formedso as to include a part or all of the functional blocks. The LSI mayinclude a data input and output coupled thereto. The LSI here may bereferred to as an IC, a system LSI, a super LSI, or an ultra LSIdepending on a difference in the degree of integration.

However, the technique of implementing an integrated circuit is notlimited to the LSI and may be realized by using a dedicated circuit, ageneral-purpose processor, or a special-purpose processor. In addition,a Field Programmable Gate Array (FPGA) that can be programmed after themanufacture of the LSI or a reconfigurable processor in which theconnections and the settings of circuit cells disposed inside the LSIcan be reconfigured may be used. The present disclosure can be realizedas digital processing or analogue processing.

If future integrated circuit technology replaces LSIs as a result of theadvancement of semiconductor technology or other derivative technology,the functional blocks could be integrated using the future integratedcircuit technology. Biotechnology can also be applied.

The object detection apparatus according to the present disclosure iscapable of detecting a moving object with enhanced reliability andstability, and the object detection apparatus may be applied to anavigation apparatus, an automatic driving control apparatus, or thelike.

What is claimed is:
 1. An object detection apparatus to be installed ona vehicle, the object detection apparatus comprising: an input portwhich, in operation, receives pieces of information on a plurality ofobjects in surroundings of a vehicle from a sensor installed on thevehicle, wherein each of the pieces of information on the plurality ofobjects includes at least one of direction information, distanceinformation, or relative speed information of each of the plurality ofobjects with reference to the vehicle, and receives information on atraffic environment that includes information indicating a type of aroad on which the vehicle is traveling from at least one of a navigationapparatus used in the vehicle, a traffic environment recognitionapparatus installed on the road on which the vehicle is traveling, orthe sensor, wherein the information indicating the type of the roadincludes one of information indicating an expressway, informationindicating a general road, or information indicating an intersection;controller which, in operation, determines a priority for each of thepieces of information on the plurality of objects based on acorresponding piece of information of the pieces of information on theplurality of objects and the information indicating the type of theroad, and selects at least one of the pieces of information on theplurality of objects based on the priority for each of the pieces ofinformation on the plurality of objects; and an output port which, inoperation, outputs the selected at least one of the pieces ofinformation on the plurality of objects to an in-vehicle apparatus thatcontrols the vehicle.
 2. The object detection apparatus according toclaim 1, wherein a priority for a piece of information includingdistance information indicating a first distance is increased comparedto a priority for a piece of information including distance informationindicating a second distance greater than the first distance.
 3. Theobject detection apparatus according to claim 1, wherein, in a casewhere the information indicating the type of the road includes theinformation indicating the expressway, a priority for a piece ofinformation including direction information indicating an oncomingdirection is reduced compared to a priority for a piece of informationincluding direction information not indicating the oncoming direction.4. The object detection apparatus according to claim 1, wherein, in acase where the information indicating the type of the road includes theinformation indicating the intersection, a priority for a piece ofinformation including direction information indicating an oncomingdirection is increased compared to a priority for a piece of informationincluding direction information not indicating the oncoming direction.5. The object detection apparatus according to claim 1, wherein, in acase where the information indicating the type of the road includes theinformation indicating the general road, a priority for a piece ofinformation including direction information indicating an oncomingdirection and relative speed information indicating a first speed isincreased compared to a priority for a piece of information includingdirection information not indicating the oncoming direction orindicating relative speed information indicating a second speed lowerthan the first speed.
 6. The object detection apparatus according toclaim 1, wherein the controller, in operation, determines whether or nottransmitting all the pieces of information on the plurality of objectsto the in-vehicle apparatus is possible, and wherein, in a case wherethe controller determines that transmitting all the pieces ofinformation on the plurality of objects to the in-vehicle apparatus isnot possible, the controller determines the priority for each of thepieces of information on the plurality of objects.
 7. The objectdetection apparatus according to claim 1, wherein the controller, inoperation, determines whether or not a total number of objects in theplurality of objects is larger than a predetermined value, and wherein,in a case where the controller determines that the total number ofobjects in the plurality of objects is larger than the predeterminedvalue, the controller determines the priority for each of the pieces ofinformation on the plurality of objects.
 8. The object detectionapparatus according to claim 1, wherein the in-vehicle apparatus is atleast one of a device configured to control driving of the vehicle or adevice configured to control one or more contents displayed on a displayapparatus in the vehicle.
 9. The object detection apparatus according toclaim 1, wherein the output port outputs the selected at least one ofthe pieces of information to the in-vehicle apparatus sequentially inorder of priority from high to low.
 10. The object detection apparatusaccording to claim 1, wherein the input port receives the pieces ofinformation on the plurality of objects time-sequentially, wherein thecontroller, in operation, attempts to repeatedly perform a targettracking process on the plurality of objects based on the pieces ofinformation on the plurality of objects, and wherein the controller, inoperation, determines a priority for each of the plurality of objectsbased on the pieces of information on the plurality of objects, theinformation indicating the type of the road, and a result of the targettracking process.
 11. The object detection apparatus according to claim1, wherein the information on the traffic environment further includesat least one of information indicating a building adjacent to the roadon which the vehicle is travelling, or information indicating a currentweather condition.